In order to reduce the nitrous oxides (NO.sub.x) in the exhaust gases of internal combustion engine it is known to feed back a proportion of the exhaust gas from the exhaust gas side of the internal combustion engine to the induction side of the same. The amount of exhaust gas fed back must however be regulated very accurately in dependence on several factors, such as for example the temperature of the engine (temperature of the coolant), the amount of induced air and the speed of rotation, in order to avoid poor running in the start-up phase and to ensure as high as possible a reduction of the nitrogen oxide proportions during operation. In order to regulate the amount of exhaust gas fed back a valve is provided between the exhaust gas feedback pipe coming from the exhaust manifold and the connecting pipe leading to the induction side of the engine, this valve being controlled by an regulating actuator, e.g. a vacuum-sensitive diaphragm. In order to optimise the amount of exhaust gas fed back an electronic regulator is used, which controls the vacuum acting on the diaphragm in dependence on the aforesaid different parameters and thus controls the valve position of the valve. Such an electronic control (Pressure Drop Feedback Electronics .delta.PFE) comprises a programmed electronic control module, to whose inputs are applied the speed of rotation, coolant temperature and the air throughput. The control module sends a signal to a vacuum regulator which controls the vacuum acting on the diaphragm. The diaphragm opens the valve of the valve device in accordance with the vacuum pressure. A control throttle orifice is provided in the exhaust gas feedback pipe. A transducer compares the pressure obtaining before and after the throttle orifice and sends a feedback signal to the control module. Any deviation in this again effects control of the valve by means of the vacuum regulator and the diaphragm.
In the initially mentioned known valve device a housing consisting of a die casting is provided, having relatively large dimensions and a correspondingly high weight. In order to ensure satisfactory performance of the valve, the valve seat is formed as a separate turned part and is fitted into the cast housing. The exhaust gas feedback pipe is provided with a backnut and a beading retaining the same. The back nut is screwed into a thread on the exhaust gas inlet of the cast housing. The cast housing has a flange on the exhaust gas outlet side, to which the connecting pipe provided with a complementary flange is fixed. The diaphragm housing is fixed to the cast housing by three screws. The manufacture of the cast housing is however relatively expensive, since the valve seat is separately made and has to be fitted into the cast housing. Moreover the thread on the exhaust gas inlet and the flange on the exhaust gas outlet have to be machined. In addition it is necessary to provide the exhaust gas feedback pipe with a back nut and the beading and to provide the connecting pipe with a complementary flange. The cast housing is also relatively large and heavy. On account of the large mass stable brackets, which are thus also expensive to manufacture and heavy, are needed to fix it. Since the angular position of an inlet bend provided on the cast housing is fixed relative to the flange provided on the exhaust gas outlet and cannot be altered, different cast housings are mostly required for different engine types, which additionally increases the manufacturing costs. In all the assembly costs are relatively large, since the valve seat must be pressed into the cast housing and the screwing of the exhaust gas feedback pipe and connecting pipe to the cast housing require a corresponding expenditure of time.